Another mystery device


A crawl space could have sump pump in the lowest corner


I was thinking maybe there is a french drain or something like that under my house that i didn’t know about. if thats the case then that would be awesome news. Gonna wait and maybe go down there next weekend and take a look and see what I find. I’ve only crawled under one side of this house since I’ve owned it over the past two years and that was to fix the drier vent hose that was broken which was during the first six months of me living here.


They usually install a pump one of two ways. Either the pump will just be set at the lowest point next to the foundation wall or there will be a well dug deeper the pump sits in. The latter would have a manhole look to it with a cover over it.
If you do have one then it’s something you need to know. If something goes wrong like a float sticks or pump fails, the damage could be enormous.
Sumps are using on their own circuit but could also be a branch for outdoor receptacles.


Dont bother looking for anything large like a sump pump or anything septic related, the wattage is simply too small for those applications.

That being said I don’t know where else to look without knowing more about your devices. Is the cycle time always the same about of time?


@samheidie I wasn’t referencing a septic
Pump, just a gray water basin pump which would
Easily fall into the voltage/wattage range. Septic pump would require much more.
The pump I had installed until I put a French drain around the house was about 150 watts


The times vary so not on a timer but the power usage is consistent


The first thing I notice is that it cycles more during the day than it does in the afternoon and evening.
Could it be related to your heating system like a fan or dumidifier? While people are at home, the body heat, lights and using electric devices can generate enough heat for heat sources to cycle a little less.
Depending on your thermostat and sensors, a fan could be circulating


Sense has already found the HVAC fan and labeled it according…I think i just figured it out, well maybe. So my youngest has a Vicks humidifier in her room that i thought was unplugged but wasn’t. I just moved one of the smart plugs to it to see if it is the culprit.


I doubt it’s a small portable humidifier but I could be wrong. I’m thinking a cool air would use less electricity and warm would use more.
You’ve spent a lot of time sleuthing this detection. For me it’s an enjoyable task, any and all detections are. Especially now since my detections are going in reverse and I have about ten detections missing completely.


Well the mystery motor is on again and it is officially not the Vicks humidifier.


Inside a refrigerator there is a circulation fan that pushes the cold air between freezer and fridge sides. Also a damper door that opens and closes with it. I’m wondering if sense has found this small fan. Or if it’s the fan down at your compressor of fridge or freezer. Can you see if this fan is coming on at the same times as refrigerator or freezer compressor?


My refrigerator is on a HS110 smart plug so it cant be the fridge.


Does what the smart plug show and what sense show as wattage used line up? Are they the same. I have devices that were detected before using a smart plug and remain detected after moving them to a smart plug.
If you got the sense detection first then moved to smart plug then it will still show and tag under sense like the smart plug is t there


I checked and it looked like it might so i did some testing and “motor 2” still turned on and off when the fridge was turned off.


This is what motor 2 looks like over the past week. Not 100% sure yet but it looks like it was using less power when it was warmer out and more power when it was colder. Its currently 29F outside and 42F in my attic and 49F under my house in the crawlspace.


Thanks for the additional information. I just wanted to let you know to not hold the wattage difference as gospel in your investigation. In my experience, my heat pump will change its detected wattage every now and then and is confirmed by a ‘new model’ pushed to the Sense device.


Okay so the return for my HVAC is in the ceiling about 5 feet from my desk and as i am sitting here this morning getting ready for work the heat turned on and was running for a few minutes and then it sounded like someone turned the speed up just a little and then i got a notification on my phone that motor 2 turned on and sure enough about 2 minutes later it sounded like the fan slowed down and then a second later i got a notification that motor 2 turned off. seems like it might be part of the HVAC/furnace system but i don’t want to definitively say that yet until i do more investigating.


You might want to check the nameplate of your air handler to see what size breaker it actually calls for. It would be unusual to have a modern residential air handler need 120v/30a. I suspect the breaker is oversized from a previously installed unit.

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Does your HVAC supply to two different zones ? Do you have a balancing damper that diverts air between two different rooms/zones ? Two minutes seems like a long time to readjust, but just tossing out ideas…


I misspoke, its actually a 20A breaker on the furnace not 30A. The house was built in 2000 and the HVAC and furnace are original to the house.